The process of making bean milk and bean curd using a traditional method is as follows.
First, beans are washed, and the washed beans are soaked in water for many hours. The soaked beans are ground by a mill or a blender to obtain an extract of beans. The extract of beans is strained through a sieve or closely perforated cloth to be divided into bean curd dregs and an extract of protein.
Next, only the extract of protein is put into a vessel, such as a pot, and boiled. At this time, the extract of protein may boil over. Thus, in order to prevent the extract of protein from boiling over, heating power must be carefully regulated by a user. After the extract of protein is boiled for a predetermined period, additives, including sugar and salt, are added to the extract of protein. Thus, the bean milk is finished.
Meanwhile, when the user desires to make watery bean curd or bean curd, a coagulant, such as calcium sulphate, is stirred into the boiled extract of protein. After several minutes, the watery bean curd is made. Further, when the watery bean curd is pressed in a frame to have a predetermined shape, the bean curd is made.
However, the conventional method of making bean milk and bean curd has a problem in that several processes are individually executed, thus it is inconvenient and complicated to make the bean milk and the bean curd, and it takes longer time to make the bean milk and the bean curd, thereby the conventional method is inefficient.
In order to solve the problems, there have been proposed various devices for easily and conveniently making bean milk and bean curd at home. For example, there are Korean Patent No. 99-225772, Korean Patent No. 2000-228659, Korean U.M. Registration No. 158856, Korean U.M. Registration No. 250843, etc, that are disclosed by the applicant of the present invention. The Korean Patent No. 99-225772 was published on Oct. 15, 1999, and is titled “household bean curd maker”. The Korean Patent No. 2000-228659 was published on Mar. 15, 2000, and is titled “household bean curd maker”. The Korean U.M. Registration No. 158856 was registered on Jul. 16, 1999, and is titled “household bean curd maker”. The Korean U.M. Registration No. 250843 was registered on Oct. 5, 2001, and is titled “household bean curd maker with fixed-type blade unit”.
A conventional household bean milk and bean curd maker will be described in the following with reference to FIG. 1.
FIG. 1 is a sectional view of the conventional household bean milk and bean curd maker. As shown in FIG. 1, the conventional household bean milk and bean curd maker includes a housing 11 which has a cavity to contain water therein. A main body 12 is provided on an upper portion of the housing 11 to open or close the housing 11, like a lid. A drive motor 13 is installed in a predetermined portion of the main body 12, and generates rotating power when electricity is applied to the drive motor 13. A drive shaft 14 transmits the rotating power from the drive motor 13. A cutting blade 15 is provided at an end of the drive shaft 14. A heater 16 downwardly extends from the main body 12, and generates heat when electricity is applied to the heater 16, thus heating an interior of the housing 11. A temperature sensing bar 17 detects the temperature of the interior of the housing 11. A filter net 18 is detachably mounted to a predetermined portion of the main body 12, and contains beans therein. Further, the household bean milk and bean curd maker also includes a thermal fuse 19 coupled to a predetermined portion of the heater 16, thus preventing the electricity from being supplied to the heater 16 when the housing 11 is overheated.
The conventional household bean milk and bean curd maker constructed as described above is operated as follows.
First, a user puts the beans into the filter net 18. The filter net 18 containing the beans is assembled with the main body 12, and then water is put into the housing 11. Thereafter, the main body 12 is placed on the upper portion of the housing 11 so that the filter net 18 is put into the housing 11.
Next, when a power switch (not shown) is turned on to apply electricity to the household bean milk and bean curd maker, a control unit (not shown) outputs a control signal to operate the heater 16 and the temperature sensing bar 17. At this time, a primary heating process is executed while maintaining a predetermined temperature. Thereafter, as the drive motor 13 is operated, the beans contained in the filter net 18 are ground by the cutting blade 15 provided at the end of the drive shaft 14.
As such, while the beans are ground, the turbulence of water contained in the housing 11 is caused by rotation of the cutting blade 15. By the turbulence, bean grains which are finely ground by the cutting blade 15 come out of the filter net 18. Thus, the beans ground by the cutting blade 15 are divided into bean-curd dregs which remain in the filter net 18, and the extract of protein which flows out of the filter net 18.
Thereafter, the control unit (not shown) outputs a control signal to operate the heater 16 and the temperature sensing bar 17. At this time, a secondary heating process is executed while maintaining a predetermined temperature. Through the above-mentioned process, bean milk is obtained.
When the user desires to make bean curd, the user takes the heated extract of protein out of the housing 11. Next, the coagulant is added to the heated extract of protein so as to coagulate the extract of protein. Thereafter, the coagulated protein is pressed in the frame to produce the bean curd.
In such a household bean milk and bean curd maker, the thermal fuse 19 serving as the overheat prevention device is coupled to the heater 16. Thus, when the housing 11 is overheated during making the bean milk and bean curd, the thermal fuse 19 is electrically opened, thus preventing electricity from being supplied to the heater 16, and thereby protecting the user from an electric shock.
However, the conventional overheat prevention device for the household bean milk and bean curd maker has a problem in that the thermal fuse 19 does not detect the internal temperature of the housing 11 but detects the temperature of the heater 16 positioned in the main body 12, so that the internal temperature of the housing 11 is not accurately detected, thus causing the household bean milk and bean curd maker to overheat.